Method of and apparatus for treating waste paper

Abstract

The invention relates to a method of treating waste paper, wherein the waste paper is steeped, under certain circumstances chemically treated at the same time, and is thereafter adjusted to a lower substance density and sorted. Furthermore, the invention relates to apparatus for performing such a method.

We claim: 
     
       1. A method of treating waste paper comprising dissolvable fibrous material and non-dissolvable material without comminution of the non-dissolvable material, the method comprising: steeping the waste paper in water for between 10 and 120 minutes at a substance density of between 10% and 40%;   repeadedly lifting and dropping the waste paper as it is steeped;   adding sufficient diluting water to the steeped material to achieve a substance density of between 2% and 6%;   circulating and mixing the steeped material and the diluting water in order to obtain a fibrous suspension without comminution of the non-dissolvable material;   pressurelessly feeding said fibrous suspension and said non-dissolvable material to a screening station; and   pressurelessly sorting the fibrous suspension from the non-dissolvable material.   
     
     
       2. Method according to claim 1, wherein the steeping time is between 20 and 30 minutes. 
     
     
       3. Method according to claim 1, wherein the substance density while steeping is between 15% and 30%. 
     
     
       4. Method according to claim 1 wherein the rapid circulation is effected at a substance density between 3% and 5%. 
     
     
       5. Method according to claim 1, which further comprises weighing the waste paper to be steeped and computing the quantity of water to be added thereto to yield a predetermined substance density.